Ovens, finger ducts therefor, and methods for distributing air in a finger duct

ABSTRACT

The present invention is directed to ovens for heat treating products and may include food preparation ovens for preparing pizza and similar types of food products. The oven include finger ducts having longitudinally-extending staggered angled air deflectors to aid in distribution of the heated air into the oven.

CLAIM TO PRIORITY AND CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/915,012, filed Apr. 30, 2007, entitled “Ovens, And Burner TubeAssemblies, Cold Air Return Baffles, Finger Ducts, And Removable WheelsTherefor”, which is hereby incorporated herein by reference in itsentirety.

This application is related to commonly owned, and co-filed U.S. patentapplication Ser. No. ______, entitled “Ovens, Burner Tube Assemblies,And Methods For Delivering Air To A Gas Power Burner,” by Bramhall,(Docket No. 2869.015A); U.S. patent application Ser. No ______, entitled“Ovens Having A Cold Air Return Baffle And Methods For Circulating AirIn An Oven,” by Bramhall, (Docket No. 2869.015B); and U.S. patentapplication Ser. No. ______, entitled “Methods For Moving Ovens, AndOvens Having Means For Releasably Attaching To A Plurality Of Casters,”by Bramhall, (Docket No. 2869.015D), which are hereby incorporatedherein by reference in their entirety.

FIELD OF THE INVENTION

This invention relates generally to ovens, and more specifically, tofinger ducts for ovens for heat treating products.

BACKGROUND OF THE INVENTION

Ovens for heat-treating products oftentimes employ a burner forcombusting a fuel such as gas or an electric means for heating the oven.Food preparation ovens such as food preparation ovens for preparingpizza and other types of food products employ jets of hot gaseous fluidsuch as hot air for baking or cooking the food product.

FIG. 1 illustrates a portion of a conventional finger duct 10 having asingle channel structure 20 and a plurality of deflectors 30. Not shownin FIG. 1 is a diffuser which is disposed on top of the baffles and acover disposed on top of the diffuser. The cover has a plurality ofopenings through which the heated gas is discharged toward the surfaceto be heated. Pressurized heated air is introduced via an inlet 40.

U.S. Pat. No. 5,025,775 issued to Crisp discloses a finger duct 44 ahaving plurality of scoop-shaped deflector vanes 66 a, 66 b, 66 c, and66 d, each attached to finger duct 44 a and extending the width offinger duct 44 a. See FIGS. 7 and 9. The front edge of each deflector 66is perpendicular to inner nozzle plate 54 a, and the back edge 70 isoutwardly curved and attached to finger duct 44 a. As air flows throughfinger duct 44 a, it tends to flow through the entire length of the ductand exit through nozzles 48 which are near the end of finger duct 44 a.Deflectors 66 provide a more uniform distribution of air flow from frontto back by deflecting a portion of the air flow nearer the front offinger duct 44 a out through nozzle 48. In addition to providing a moreuniform distribution of air flow, deflectors 66 redirect the flow of airwithout creating high and low pressures within finger duct 44 a.

U.S. Pat. No. 6,192,877 issued to Moshonas et al. disclose a blown airdistributor for a convection oven. The blown air distributors comprisesa plurality of finger ducts mounted in parallel on a single plate havingopposite side edges each slidably receivable in a guide way provided ona corresponding side wall of the baking chamber. The blown airdistributor has an adjustable deflector in each finger duct to control aflow of heated air therein. Preferably, each of the adjustable deflectorcomprises an inclined baffle wall having two opposite side edges securedto a corresponding sidewall of the finger duct. The baffle wall has aback end extending towards the inlet of the finger duct and a front endextending towards a front end wall of the finger duct. A controllableplate having an end hinged to the back end of the baffle wall is alsoprovided. The controllable plate is pivotable between a downwardposition where most of the heated air received through the inlet of thefinger duct is directed towards the front end wall of the finger ductand an upward position where most of the heated air received through theinlet of the finger duct is directed generally under the baffle wall.The plate is controllable by means of an operating handle mounted on anouter surface of the finger duct and operatively connected to thecontrollable plate to pivot the plate between the downward and theupward position.

U.S. Pat. No. 6,526,961 issued to Hardenburger discloses a conveyor ovenhaving lower, middle and upper hot air manifold fingers. The middlefinger has a lower air plate with air holes, an upper air plate with airholes, and an internal baffle. The internal baffle has a series of holesthat allow about ⅓ of the air flow to this finger to travel downward andout through the lower air plate.

There is a need for further ovens and finger ducts therefore.

SUMMARY OF THE INVENTION

The present invention, in a first aspect, is directed to a finger ductfor directing heated air in an oven. The finger duct includes anelongated housing an having inlet at one end of the housing forreceiving a flow of heated air, and a plurality of outlets spacedgenerally along a length of the housing for directing heated air towardsa surface to be heated in the oven. At least one elongated divider isdisposed in and along the length of the housing to define at least aplurality of longitudinally-extending channels in the housing. Aplurality of spaced-apart angled deflectors is disposed in a staggeredpattern in the plurality of longitudinally-extending channels fordirecting the heated air towards the plurality of openings.

The present invention, in a second aspect, is directed to an oven forheat treating a product. The oven includes a housing having a frontsidewall, a rear sidewall, a right sidewall, a left sidewall, a top, abottom, and an interior wall extending between the right sidewall andthe left sidewall to define a first chamber and a second chamber in thehousing. Means are provided for heating air in the first chamber. Anelongated finger duct as described above is in fluid communication withthe first chamber for receiving heated air from the first chamber anddischarging the heated air along a length of the finger duct in a firstdirection towards a surface to be heated in the second chamber.

The present invention, in a third aspect, is directed to a method fordistributing air in a finger duct for use in an oven for heat treating aproduct. The method includes introducing a flow of heated air into aninlet of the finger duct, dividing the flow of heated air into aplurality of longitudinally-extending channels in the finger duct,staggering the deflection of the flow of air in adjacent ones of theplurality of longitudinally-extending channels toward a plurality ofoutlets in the finger duct, and discharging the deflected flow of air ineach of the plurality of longitudinally-extending channels fromrespective plurality of outlets in the finger duct.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the concluding portion of thespecification. The invention, however, may best be understood byreference to the following detailed description of various embodimentsand the accompanying drawings in which:

FIG. 1 is a perspective view of a portion of a prior art finger duct;

FIG. 2 is a front perspective view of one embodiment of an oven inaccordance with the present invention;

FIG. 3 is diagrammatic side elevational view of a portion of the oven inFIG. 2;

FIG. 4 is an end view of the portion of the oven of FIG. 3;

FIG. 5 is a top view of the portion of the oven of FIG. 3;

FIG. 6 is a perspective view, partially cut-away, of a housing of afinger duct in accordance with the present invention;

FIG. 7 is a view taken along line 7-7 in FIG. 6; and

FIG. 8 is a flowchart of one embodiment of a method for distributing airin a finger duct for use in an oven for heat treating a product.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to ovens for heat treating productsand may include ovens for heat treating products such as ovens forpreparing pizza and similar types of food products. For example, theovens may be configured as an impingement oven having a conveyor whereinfood products are baked or cooked by means of jets of hot gaseous fluidsuch as hot air and wherein the hot air jets are impinged directly uponlocalized areas of the food product.

FIG. 2 illustrates an oven 100 in accordance with the present inventionfor heat treating products and may include an oven for preparing pizzaand similar types of food products. For example, a gas power burner maybe used in an impingement oven having a housing 112 and a conveyor 120wherein food products are baked or cooked by means of jets of hotgaseous fluid such as hot air and wherein the hot air jets are impingeddirectly upon localized areas of the food product. Alternatively, anelectrical heating element may be employed instead of the gas burner. Ashroud 130 covers a conveyor drive motor operatively connected via agear motor, a sprocket, and a chain, for moving the conveyor. It will beappreciated that a plurality of such ovens may be employed in a stackedconfiguration.

In one aspect, the present invention is directed ovens having animproved finger duct. As best shown in FIGS. 3-5, oven 112 includes ahousing having a front sidewall 200, a rear sidewall 210, a rightsidewall 220, a left sidewall 230, a top 240, and a bottom 250. Aninterior wall 260 extends between the right sidewall and the leftsidewall to define a first chamber 270 in which air is heated and asecond chamber 280 which may include conveyor 120 (FIG. 4) for movingthe products to be heat treated through the oven. Finger ducts 330 and332 discharge heated air from plurality of outlets in the finger ducts.

FIG. 6 illustrates one embodiment of a finger duct 400 in accordancewith the present invention. Finger duct 400 includes housing 405, aplurality of longitudinally-extending dividers 410 which define aplurality of narrow longitudinally-extending channels 412, 414, and 416.Disposed in the narrow longitudinally-extending channels is a pluralityof staggered angled air deflectors 420. The deflectors may be disposedin a staggered checkered pattern configuration. As shown in FIG. 7, adiffuser 450 may be disposed on top of the staggered deflectors anddividers and a cover 460 of housing 405 having a plurality of outlets465 may be disposed on top of the diffuser. The deflectors may be placedand sandwiched between the longitudinally-extending channels (need notbe welded) and held in place by the diffuser. Pressurized heated air isintroduced via inlet 470 (FIG. 6). Deflectors 420 are disposed on anangle, e.g., on angle less than about 45 degrees. Above 45 degrees mayresult in the air flow stalling. The finger duct havinglongitudinally-extending dividers and staggered deflectors enhances theairflow exiting the finger duct. The number, spacing, depth, and angleof the deflectors may be optimized so that the pressure and temperatureis generally constant over the area to be heated, and/or so that theheated air is generally evenly discharged from the cover of the housing.

FIG. 8 illustrates a flowchart of a method 500 for distributing air in afinger duct for use in an oven for heat treating a product. Method 500includes at 510, introducing a flow of heated air into an inlet of thefinger duct, and at 520, dividing the flow of heated air into aplurality of longitudinally-extending channels in the finger duct. Theflow of air in each of the plurality of longitudinally-extendingchannels is directed toward a plurality of outlets in the finger duct at530. At 540, the deflected flow of air in each of the plurality oflongitudinally-extending channels is discharged from respectiveplurality of outlets in the finger duct.

The various components of the present invention described above may beincorporated into the food preparation ovens disclosed in U.S. Pat. No.4,846,143 issued to Csadenyl, U.S. Pat. No. 5,025,775 issued to Crisp,and applicant's co-filed U.S. patent applications as noted above, theentire subject matter of these patents and applications beingincorporated herein by reference.

Thus, while various embodiments of the present invention have beenillustrated and described, it will be appreciated to those skilled inthe art that many changes and modifications may be made thereuntowithout departing from the spirit and scope of the invention.

1. A finger duct for directing heated air in an oven, said finger ductcomprising: an elongated housing having an inlet at one end of thehousing for receiving a flow of heated air, and a plurality of outletsspaced generally along a length of the housing for directing heated airtowards a surface to be heated in the oven; at least one elongateddivider disposed in and along the length of said housing to define atleast a plurality of longitudinally-extending channels in said housing;and a plurality of spaced-apart angled deflectors disposed in astaggered pattern in said plurality of longitudinally-extending channelsfor directing the heated air towards the plurality of openings.
 2. Thefinger duct of claim 1 wherein said at least one elongated dividercomprises a plurality of elongated dividers to define a plurality oflongitudinally-extending channels, and said plurality of angleddeflectors comprise a staggered checkered pattern in said plurality oflongitudinally-extending channels.
 3. The finger duct of claim 1 whereinsaid plurality of angled deflectors is sandwiched between said dividerand said housing in the longitudinally-extending channels.
 4. The fingerduct of claim 1 wherein said plurality of angled deflectors comprises aplurality of angled deflectors disposed at an angle of less than about45-degrees relative to the length of said housing.
 5. The finger duct ofclaim 1 wherein the number of said plurality of angled deflectors, thespacing between said angled deflectors, and the angle of said angleddeflectors are optimized to result in a discharge of heated air from theplurality of outlets openings generally evenly along said length of saidhousing.
 6. The finger duct of claim 1 wherein the number of saidplurality of angled deflectors, the spacing between said angleddeflectors, and the angle of said angled deflectors are optimized sothat a pressure and a temperature are generally constant over thesurface to be heated.
 7. The finger duct of claim 1 wherein said housinglongitudinally tapers from said inlet opening to a distal end of thehousing.
 8. The finger duct of claim 1 further comprising a diffuserdisposed between said plurality of outlets and said at least onedivider.
 9. The finger duct of claim 1 wherein said housinglongitudinally tapers from said inlet opening to a distal end of thehousing, said at least one elongated divider disposed in and along thelength of said housing comprises a plurality of elongated dividers, andsaid plurality of angled deflectors comprises a plurality of angleddeflectors disposed in a staggered checkered pattern in said pluralityof longitudinally-extending channels for directing the heated air towardthe plurality of outlets in said housing.
 10. The finger duct of claim 9wherein said plurality of angled deflectors is sandwiched between saiddivider and said housing in the longitudinally-extending channels. 11.The finger duct of claim 9 wherein said plurality of angled deflectorscomprises a plurality of angled deflectors disposed at an angle of lessthan about 45-degrees relative to the length of said housing.
 12. Thefinger duct of claim 9 wherein the number of said plurality of angleddeflectors, the spacing between said angled deflectors, and the angle ofsaid angled deflectors are optimized to result in a discharge of heatedair from the plurality of outlets openings generally evenly along saidlength of said housing.
 13. The finger duct of claim 9 wherein thenumber of said plurality of angled deflectors, the spacing between saidangled deflectors, and the angle of said angled deflectors are optimizedso that a pressure and a temperature are generally constant over thesurface to be heated.
 14. The finger duct of claim 9 further comprisinga diffuser disposed between said plurality of outlets and said at leastone divider.
 15. An oven for heat treating a product, said ovencomprising: a housing having a front sidewall, a rear sidewall, a rightsidewall, a left sidewall, a top, a bottom, and an interior wallextending between said right sidewall and said left sidewall to define afirst chamber and a second chamber in said housing; means for heatingair in said first chamber; an elongated finger duct of claim 1 in fluidcommunication with said first chamber for receiving heated air from saidfirst chamber and discharging the heated air along a length of saidfinger duct in a first direction towards a surface to be heated in saidsecond chamber.
 16. An oven for heat treating a product, said ovencomprising: a housing having a front sidewall, a rear sidewall, a rightsidewall, a left sidewall, a top, a bottom, and an interior wallextending between said right sidewall and said left sidewall to define afirst chamber and a second chamber in said housing; means for heatingair in said first chamber; an elongated finger duct of claim 9 in fluidcommunication with said first chamber for receiving heated air from saidfirst chamber and discharging the heated air along a length of saidfinger duct in a first direction towards a surface to be heated in saidsecond chamber.
 17. A method for distributing air in a finger duct foruse in an oven for heat treating a product, the method comprising:introducing a flow of heated air into an inlet of the finger duct;dividing the flow of heated air into a plurality oflongitudinally-extending channels in the finger duct; staggering thedeflection of the flow of air in adjacent ones of the plurality oflongitudinally-extending channels toward a plurality of outlets in thefinger duct; and discharging the deflected flow of air in each of theplurality of longitudinally-extending channels from respective pluralityof outlets in the finger duct.
 18. The method of claim 17 wherein thedeflecting the flow of air in adjacent ones of the plurality oflongitudinally-extending channels comprises deflecting the flow of airin the plurality of longitudinally-extending in a staggered checkeredpattern.
 19. The method of claim 17 further comprising distributing thedischarge of heated air generally evenly from the plurality of outlets.20. The method of claim 17 further comprising tapering the plurality oflongitudinally-extending channels from the inlet opening to a distal endof the housing.
 21. The method of claim 17 further comprising diffusingthe flow of air out of the plurality of outlets.